Ments



June 2, 1 931. F. G. LILJENROTH HETHOD 0F PRODUCING HYDROGEN ANDPHOSPHORIC ACID Filed Kay 20, 1924 CATALYST CONDENSER PHOSPHORU6 FuRNAcEComosnszn CONDENSER PREHEATJNG D CHTALYST Patented June 2, 1931 Um'rao.STATES PATENT: OFFICE FBANS GEORG LILJ'ENRO TH, OIi STOGKSUN'D, SWEDENQASSIGNOR, BY MESNE ASSIGN- HEN'IS, TO DU IONT AMMONIA CORIEORA'IION, OFWILMINGTON, DELAWARE, A COR- PORATION OF DELAWARE METHOD OF PRODUCINGHYDROGEN AND IHOSPHORIC"ACID Application filed May 20, 1924, Serial No.

The present invention relates to an improved method of producinghydrogen and phosphoric acid, involvin the preparation of freephosphorus and t e reaction thereupon by steam under such conditions asto produce phos horic anhydrid and free hydrogen, and the o ject of theinvention is to efiect certain economies in the process. The presentapplication is in part a continuation of m application 622,401 filedMarch 2, 1923,

wherein the method of producing hydro en and phosphoric acid, as hereindescribe is broadly covered. The accompanying drawings are diagrammaticelevations (partly in section) of apparatus suitable for carrying .outthe present invention. Fig. 1 shows one form of apparatus and Fig. 2shows a modified form ofapparatus, it being understood that theapparatus is shown by way of example-only, and not as limiting theinvention thereto.

In said drawings A represents an'electric furnace, provided withelectrodes B, and having a tap hole C for drawing 03 the slag. Themixture of a suitable phosphate (such as phosphate rock tricalciumphosphate) a reducing agent such as carbon in the form of coal or coke,and a fluxin agent such as silica or silicious material, is ed into thefurnace A, and is heated therein by means of an electric arc, up to a hih temperature, sufiicient to form a freely uid slag, whereby phosphorusin the elemental state is formed and v vaporized, together with carbonmonoxid.

The gases and vapors evolved are conducted to a condenser K, which ismaintained at about the boiling point of water or at least above themeltmg point of phosphorus,

whereb the elemental phosporus condenses into a iquid state, and thecarbon monoxid is drawn off through ypipe k. In the form of apparatusshown in 1g. 1 a part of the carbon monoxid can be burned for raisingsteam,-

or for superheat-ing steam, or for preheating the charge, or forfurnishing heat or power for any purposes, while another-portion of thecarbon monoxid can be led through ipe' 'h and conducted through apreheater I, mixed with steam, and then conducted into the cata lyzingchamber J, containing a catalyst such,

714,546, and in Sweden August 28, 1922.

for example, as iron oxid maintained at a temperature of around 350 to450 0., whereby the carbon monoxid and steam react to produce freehydrogen and carbon dioxid, which as mixture is drawn off through thefan. he steam can be introduced through pipe 2', or if it is desired toproduce a mixture of hydrogen and nitrogen, some air can be introducedwith said steam. In the apparatus shown in Fi 2 the gases and vaporsleave the furnace K through a pipe or flue E, and

. a means for recovering some portion or all of apparatus shown in Fig.2 further comprises a pipe it through which the carbon'monoxid leavesthe condenser K, a branch 71.2 of which may lead to a hydrogen-producingapparatus as shown at IJ in Fig. 1 and it, another branch of this maylead to the lower end of a rotary kiln F, or other device for preheatingthe charge of materials to be introduced into the electric furnace. Thegas may be burned in F by means of air supplied in regulated quantitiesby fan S. The charge may be introduced into the preheater F by means ofthe hopper D and at the upper end of the reheater, a fan or ventilator Tis placed.

he heat produced by the burning of the carbon monoxid gas in thepreheater F preheats the charge of material therein, to a hightemperature, but not suflicient to evolve elemental phosphorus, afterwhich the material drops through the large pipe or flue p, into theelectric furnace A. The speeds and dimensions of the ventilators R,'Sand T are so chosen that there is a slow streamin of gas in a downwarddirection throught e pipe p and out through the pipe E.

The phosphorus collecting in the condenser K may pass through thepipe 70into the conversion chamber L, which is supplied with high temperatureste am (hydrogen monoxide) through the pipe 1.

too

the phosphoric acid to produce If desired also a small amount of air canbe introduced with the steam, in order to burn a part of the phosphorusto phosphoric anhydrid, in order that the final exit gases may containnot only hydrogen but nitrogen, and if desired the amount of air sointroduced can be such as to leave a mixture of hydrogen and nitrogen inthe proportions of about 3 to 1 by volume, for the production therefromof ammonia, by a synthetic process.

Thus, with a properly regulated propertion of air and steam, thereactions taking It is understood that if enough air to burn all thephosphorus were to be admitted, the second reaction only would becarried out and no free hydrogen would be formed.

The chamber L can containa catalytic material or filling material ifdesired, suitable catalytic materials being those covered in application663,493 filed September 18, 1923, such as the metals nickel, cobalt,ruthenium, rhodium, palladium, osmium, irridium,

platinum, manganese, chromium, molybde- V num, tungsten, uranium,copper, silver, gold or the oxids of these metals, or various mixturesof the same, alone or deposited on carriers. The metals, if used as suchmay be in the form of fine wire gauze. With the use of catalyzers of thecharacter mentioned the reaction will take place at a much lowertemperature and more completely, although if the temperature of thechamber Lbe held up to about 1000 0., then no catalyzer is necessary.

The gases and vapors then pass into a coolor G and an absorber orcondenser H, and the latter may, for example, be a wet condenser,

or an electrostatic precipitator.

The remaining gases are then drawn on through the pump M and mayconveniently be converted into ammonia, which ammonia can besubsequently caused to combine with ammonium phosphate.

What I claim is:

A process of treating phosphates which comprises heating a mixtureincluding phosphate material,'a solid reducing agent and a siliceousmaterial, to a temperature incapable of liberating any substantialamount of its phosphorus, by combustion of gas in direct contacttherewith, further heating the charge to a temperature sufiicient todrive ofl' substantially all its phosphorus in the elemental condition,and separating the phosphorus from the fixed gas present, and utilizinga part of said fixed gas, at least, in saidfirst mentioned step.

In testimony whereof I have signed my name.

FRANS GEORG LILJENRQTH.

